• BMB Reports
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• 제41권7호
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• pp.555-560
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• 2008

The interaction of the rod GTP binding protein, Transducin ($G_t$), with bleached Rhodopsin ($R^*$) was investigated by measuring radiolabeled guanine nucleotide binding to and release from soluble and/or membrane-bound Gt by reconstituting $G_t$ containing bound GDP ($G_t$-GDP) or the hydrolysis-resistant GTP analog guanylyl imidodiphosphate ($G_t$-p[NH]ppG) with $R^*$ under physiological conditions. Release of GDP and p[NH]ppG from $G_t$ occurred to the same extent and with the same light sensitivity both in the presence and absence of added GTP. Significant amounts of $G_t$ without bound nucleotide ($G_{t^-}$) were generated. When ROS containing bleached rhodopsin ($R^*$) were centrifuged in low ionic strength buffer, $G_{t^-}$ remained associated with the membrane fraction, whereas $G_t$-GDP remained in the soluble fraction. These results suggest that $G_t$-GDP and $G_t$-p[NH]ppG have similar affinities for $R^*$. The results also suggest that $G_{t^-}$, rather than $G_t$-GDP, is the moiety which exhibits tight, "light-induced" binding to rhodopsin.

• Asian Pacific Journal of Cancer Prevention
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• 제15권7호
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• pp.3123-3128
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• 2014

The liver is normally the major site of glucose metabolism in intact organisms and the most important target organ for the action of insulin. It has been widely accepted that insulin resistance (IR) is closely associated with postoperative recurrence of hepatocellular carcinoma (HCC). However, the relationship between IR and drug resistance in liver cancer cells is unclear. In the present study, IR was induced in HepG2 cells via incubation with a high concentration of insulin. Once the insulin-resistant cell line was established, the stability of HepG2/IR cells was further tested via incubation in insulin-free medium for another 72h. Afterwards, the biological effects of insulin resistance on adhesion, migration, invasion and sensitivity to cis-platinum (DDP) of cells were determined. The results indicated that glucose consumption was reduced in insulin-resistant cells. In addition, the expression of the insulin receptor and glucose transportor-2 was downregulated. Furthermore, HepG2/IR cells displayed markedly enhanced adhesion, migration, and invasion. Most importantly, these cells exhibited a lower sensitivity to DDP. By contrast, HepG2/IR cells exhibited decreased adhesion and invasion after treatment with the insulin sensitizer pioglitazone hydrochloride. The results suggest that IR is closely related to drug resistance as well as adhesion, migration, and invasion in HepG2 cells. These findings may help explain the clinical observation of limited efficacy for chemotherapy on a background of IR, which promotes the invasion and migration of cancer cells.

• 한국동물학회지
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• 제32권4호
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• pp.429-440
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• 1989

Spirometru erinocei의 유충인 sparganum에서 추출한 조항원 단백질을 항원으로 하여 sparganosis, cysticercosis, hydatidosis환자의 IgG 항체와 정상인의 IgG 항체를 혈청반응시켜 ELISA와 EITB에 의해 교차반응을 일으키는 비 특이항원 성분과 종특이항원 성분을 추구하였다. 1. sparganum에서 0.01 M PBS (PH 7.4)로 추출한 조항원 단백질을 SDS-PAGE로 전개하여 290 Kd에서 23 Kd범위의 분자량을 가진 25개의 단백질이 분획되었다. 2. sparganum의 조항원을 항원으로하여 ELISA로 sparganosis, cysticercosis, hydatidosis 환자의 190 항체와의 혈청 반응치는 sparganosis환자에게서는 0.44 $\pm$ 0.07에서 1.90 $\pm$ 0.03으로 negative control normal sera의 0.D (0.15 $\pm$ 0.03)를 기준으로 하였을 때 모두 양성이며 민감도(sensitivity)가 100 %이었으며 cysticercosis, hydatidosis환자혈청에서 양성반응이 나타났으며 교차반응도 있었다. 3. EITB에서는 spargancsis환자의 IgG항체에 의해 16개의 항원성분이 인지되었으며 이 중 6개의 항원성분이 정상인의 혈청에서도 인지되어 교차반응을 일으키는 항원성분이었으며 cysticercosis환자혈청에서 인지된 4개의 항원성분 중 2개의 항원성분이 sparganosis 환자혈청에서 인지된 것과 같았으며 hydatidosis환자의 190항체에 의해 인지된 19개의 항원성분 중 12개의 항원성분이 sparganosis환자혈청에서 인지된 항원 성분과 같았다. 4. 290 Kd, 200 Kd, 28 Kd의 항원성분은 sparganosis환자의 196항체에서만 인지되었고 228 Kd, 152 Kd, 66 Kd항원성분은 hydatidosis환자의 19G항체에서만 인지되었으며 66 Kd항원성분은 sparganosis, cysticercosis, hydatidosis, 정상인의 혈청에서 모두 인지되었다. We studied the serological reaction between the specific and nonspecific antigenic components from metacestode (plerocercoid) of spiromeko erimacei and IgG antibodies in sparganosis, cysticercosis. hydatidosis patients and normal human sera by ELISA and EITB. We prepared the crude extracts of sparganlim from snake, Matrix tigrina laterolis and used as antigenic components. By SDS-PAGE, we detected a total 25 peptide bands (fractions) with 290 Kd to 23 Kd molecular weight, and 8 bands of these detected bands developed strongly by silver stain. In serological test, ELISA, we recognized the cross-reaction of antigenic components reacting with IgG antibodies in heterogenous sera, cysticercosis and hydatidosis patients sera. The crude antigenic components of sparganum showed the high sensitivity in sparganosis, hydatidosis patients sera, but showed lower sensitivity in cysticercosis patients sera than the sparasanosis, hydatidosis patients sera. Sixteen antigenic components of these 25 separated bands were recognized by antibodies In sparsanosis patients sera,8 antigenic components in normal human sera, 4 antigenic components in cysticercosis patients sera and 19 antigenic compoenents in hydatidosis patients sera. The crude antigenic compnenets with 290 Kd, 200 Kd, 125 Kd and 28 Kd molecular weight was only recognized in sparganosis patients sera, but 64 Kd antigenic component was nonspecific antigenic components which were also cross-reacted with sparganosis, hydatidosis, cysticercosis patients sera and normal human sera.

• Toxicological Research
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• 제12권1호
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• pp.17-20
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• 1996

The effect of Fumonisin B1, a mycotoxin produced by Fusarium moniliforme on bacterial viruses P1 and Lambda, was investigated by the virus plaque assay. Fumonisin B1 inhibited the P1 viral multiplication in the concentration range from $100{\mu}g$/ml to $400{\mu}g$/ml. The inhibition was Fumonisin B1 concentration-dependent. Another bacterial virus Lambda multiplication was also inhibited by lower concentration of Fumonisin B1 ($10{\mu}g$/ml~$50{\mu}g$/ml). This inhibition was dependent on Fumonisin B1 and on virus-Fumonisin B1 reaction time. Sensitivity of bacteriophage Lambda to Fumonisin B1 was higher than that of P1 virus. Lambda vital DNA was treated in vitro with Fumonisin B1 at various concentration. Significant DNA fragmentation by Fumonisin 191 was observed in the agarose gel electrophoresis. Lambda viral DNA was partially digested even in the Fumonisin B1 $10{\mu}g$ and the level of its fragmentation was dependent on Fumonisin B1 amount up to $30{\mu}g$ per assay.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1865-1872
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• 2011

This study investigates the sensitivity of a gas sensor to volatile organic compounds (VOCs) at various operating temperatures and catalysts. Nano-sized powdered $WO_3$ prepared by sol-gel and chemical precipitation methods was mixed with various metal oxides. Next, transition metals (Pt, Ru, Pd, and In) were doped on the surface of the mixture. Metal-$WO_3$ thick films were prepared using the screen-printing method. The physical and chemical properties of the films were studied by SEM/EDS, XRD, and BET techniques. The measured sensitivity to VOCs is defined as the ratio ($R_a/R_g$) of resistance ($R_{air}$) of $WO_3$ film in the air to resistance ($R_{gas}$) of $WO_3$ film in a VOCs test gas. The sensitivity and selectivity of the films were tested with various VOCs such as acetaldehyde, formaldehyde, methyl alcohol, and BTEX. The thick $WO_3$ film containing 1 wt % of Ru and 5 wt % of $SnO_2$ showed the best sensitivity and selectivity to acetaldehyde gas at an operating temperature of 300 $^{\circ}C$.

• 대한산업공학회지
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• 제28권1호
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• pp.99-104
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• 2002

This paper presents a method of sensitivity analysis for the infeasible interior point method when a new variable is introduced. For the sensitivity analysis in introducing a new variable, we present a method to find an optimal solution to the modified problem. If dual feasibility is satisfied, the optimal solution to the modified problem is the same as that of the original problem. If dual feasibility is not satisfied, we first check whether the optimal solution to the modified problem can be easily obtained by moving only dual solution to the original problem. If it is possible, the optimal solution to the modified problem is obtained by simple modification of the optimal solution to the original problem. Otherwise, a method to set an initial solution for the infeasible interior point method is presented to reduce the number of iterations required. The experimental results are presented to demonstrate that the proposed method works better.

• 대한기계학회논문집A
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• 제25권3호
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• pp.529-536
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• 2001

We investigate a surface-micromachined capacitive accelerometer with the grid-type electrodes surrounded by a perforated proof-mass frame. An electromechanical analysis of the microaccelerometer has been performed to obtain analytical formulae for natural frequency and output sensitivity response estimation. A set of prototype devices has been designed and fabricated based on a 4-mask surface-micromachining process. The resonant frequency of 5.8$\pm$0.17kHz and the detection sensitivity of 0.28$\pm$0.03mV/g have been measured from the fabricated devices. The parasitic capacitance of the detection circuit with a charge amplifier has been measured as 3.34$\pm$1.16pF. From the uncertainty analysis, we find that the major uncertainty in the natural frequency of the accelerometer comes from the micromachining error in the beam width patterning process. The major source of the sensitivity uncertainty includes uncertainty of the parasitic capacitance, the inter-electrode gap and the resonant frequency, contributing to the overall sensitivity uncertainty in the portions of 75%, 14% and 11%, respectively.

• The Korean Journal of Physiology and Pharmacology
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• 제10권1호
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• pp.1-6
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• 2006

To evaluate whether metformin restores leptin sensitivity in aged rats with leptin resistance, we measured leptin sensitivity in aged (2 year old) and adult (5 month old) rats after 4 weeks of treatment with metformin (300 mg/kg/D, mixing in drinking water), by measuring food intake, body weight and visceral fat losing effects. Leptin ($15{\mu}g/D$) was administered by intracerobroventricular (i.c.v.) infusion through osmotic minipump for 1 week. Metformin treatment decreased body weight and daily food intake in both adult and aged rats compared with their control rats, however, these effects were more prominent in aged rats than in adult rats. Anorexic and fat losing responses following i.c.v. leptin were attenuated in aged rats compared to adult rats. However, these responses of aged rats to leptin were restored by metformin treatment. Moreover, serum concentration of leptin in aged rats was significantly decreased by combined treatment with metformin and leptin. These results suggest that metformin enhances leptin sensitivity in aged rat model, and that combination therapy with metformin and leptin would be helpful for treatment of aging-associated obesity.

• 한국염색가공학회지
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• 제35권3호
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• pp.179-187
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• 2023

In this study, we developed a microfiber-based flexible pressure sensor with high sensitivity and excellent skin breathability. A nonwoven fabric composed of microfibers was prepared by electrospinning, which resulted in excellent moisture permeability of the sensor (143 g∙m^-2∙h^-1). In particular, high-pressure sensitivity (0.36 kPa^-1) was achieved by introducing submicron structures on the microfiber surface by controlling the ambient humidity during electrospinning. The fabrication technology of the microfiber-based flexible pressure sensors reported in this study is expected to contribute to the commercialization of flexible pressure sensors applicable to long-term wearable health monitoring as well as virtual/augmented reality and electronic skin applications.

• 센서학회지
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• 제9권3호
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• pp.196-202
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• 2000

본 논문에서는 3축의 가속도를 검출하기 위한 새로운 방식인 브리지조합 검출원리를 제안하고, SOI 구조의 웨이퍼를 이용하여 $200^{\circ}C$ 이상 고온에서 동작이 가능한 압저항형 실리콘 가속도센서를 제작하였다. 제작된 센서의 감도는 x 및 y축이 8mV/V G, z 축이 40mV/V G 이였다. 그리고 출력전압의 비선형성은 1.6%FS, 타축감도는 약 4.6% 이하였다. 이것은 외부 연산회로를 이용하여 3축의 가속도성분을 검출하는 방법에 비해 검출방식은 간단하면서도, 특성은 거의 동일하였다. 또한 SOI 구조를 이용하여 고온에서도 안정한 동작을 하였다. 제작된 가속도센서의 오프셋전압 온도계수와 감도 온도계수는 $27^{\circ}C$에서 각각 $1033ppm^{\circ}C^{-1}$와 $1145ppm^{\circ}C^{-1}$이였다.